Functional requirements summary

The temperature of vegetation fires varies from 500 up to 1200 K, depending on the type of combustion. Their spectral density distribution occurs in the mid-wave infrared (MIR) wavelength region at 3-5 µm. Hence it is the main target for a space-born fire sensor. Reflection effects (e.g. sun glint) as sources of data misinterpretation have to be distinguished by combination of MIR and VIS (visible) channels.Furthermore temperature information have to be derived from thermal infrared (TIR) imaging data by bi-spectral data processing techniques. The so arising multi-channel system is able to detect hot spots of sub-pixel size.

The Payload Data Handling System (PDH) is the functional integrative part of the BIRD payload. It has data interfaces to all instruments, the spacecraft bus computer and the down-link telemetry channel.

Three main tasks are assigned to the PDH:

distribution of high level commands and Housekeeping extraction out of the payload data stream

science data storage, telemetry frame generation and down-link

on-board thematic data compression

The electronic units of the PDH are arranged within the electronics segment of the spacecraft. The block scheme in Figure 1 shows the functional connections of the instruments and payload units.